Add configuration with camelizing keys

.gitignore

@@ -16,5 +16,6 @@
 node_modules
 
 /docs/build/
+.DS_Store
 .cache/
 .docusaurus/

lib/panko/attribute.rb

@@ -3,10 +3,18 @@
 module Panko
   class Attribute
     def self.create(name, alias_name: nil)
-      alias_name = alias_name.to_s unless alias_name.nil?
+      alias_name = alias_name.nil? ? transform_key(name.to_s) : alias_name.to_s
       Attribute.new(name.to_s, alias_name)
     end
 
+    def self.transform_key(name)
+      case Panko.configuration.key_type
+      when Panko::Configuration::CAMEL_CASE_LOWER then name.camelize(:lower)
+      when Panko::Configuration::CAMEL_CASE then name.camelize
+      else name
+      end
+    end
+
     def ==(other)
       return name.to_sym == other if other.is_a? Symbol
       return name == other.name && alias_name == other.alias_name if other.is_a? Panko::Attribute

lib/panko/configuration.rb

@@ -0,0 +1,23 @@
+# frozen_string_literal: true
+
+module Panko
+  class Configuration
+    InitializeError = Class.new(StandardError)
+
+    CAMEL_CASE_LOWER = "camelCase"
+    CAMEL_CASE = "CamelCase"
+    AVAILABLE_KEY_TYPES = [CAMEL_CASE_LOWER, CAMEL_CASE].freeze
+
+    attr_reader :key_type
+
+    def initialize
+      @key_type = nil
+    end
+
+    def key_type=(value)
+      raise InitializeError, "Invalid key type" unless AVAILABLE_KEY_TYPES.include?(key_type)
+
+      @key_type = value
+    end
+  end
+end

lib/panko_serializer.rb

@@ -1,6 +1,7 @@
 # frozen_string_literal: true
 
 require "panko/version"
+require "panko/configuration"
 require "panko/attribute"
 require "panko/association"
 require "panko/serializer"
@@ -12,3 +13,22 @@
 # C Extension
 require "oj"
 require "panko/panko_serializer"
+
+module Panko
+  extend self
+
+  # Public: Configure Panko.
+  #
+  #   Panko.configure do |config|
+  #     config.key_type = 'camelCase'
+  #   end
+  #
+  def configure
+    yield configuration
+  end
+
+  # Public: Returns Panko::Configuration instance.
+  def configuration
+    @configuration ||= Configuration.new
+  end
+end

spec/panko/serializer_spec.rb

@@ -741,4 +741,95 @@ def created_at
       end
     end
   end
+
+  context "key_type" do
+    let(:configuration) { Panko::Configuration.new }
+    let(:data) { {"created_at" => created_at} }
+    let(:created_at) { "2023-04-18T09:24:41+00:00" }
+
+    before do
+      allow(Panko).to receive_messages(configuration: configuration)
+    end
+
+    context "with camelCase" do
+      before { configuration.key_type = "camelCase" }
+
+      context "with key_type" do
+        let(:serializer_class) do
+          Class.new(Panko::Serializer) do
+            attributes :created_at
+          end
+        end
+
+        it "has createdAt" do
+          expect(data).to serialized_as(serializer_class,
+            "createdAt" => created_at)
+        end
+      end
+
+      context "with key_type + method_fields" do
+        let(:serializer_class) do
+          Class.new(Panko::Serializer) do
+            attributes :created_at
+
+            def created_at
+              "2023-04-18T09:24:41+00:00"
+            end
+          end
+        end
+
+        it "has createdAt" do
+          expect(data).to serialized_as(serializer_class,
+            "createdAt" => created_at)
+        end
+      end
+
+      context "with key_type and alias" do
+        let(:serializer_class) do
+          Class.new(Panko::Serializer) do
+            aliases({created_at: :CreatedAt})
+          end
+        end
+
+        it "alias has priority over configuration" do
+          expect(data).to serialized_as(serializer_class,
+            "CreatedAt" => created_at)
+        end
+      end
+    end
+
+    context "with CamelCase" do
+      before { configuration.key_type = "CamelCase" }
+
+      context "with key_type" do
+        let(:serializer_class) do
+          Class.new(Panko::Serializer) do
+            attributes :created_at
+          end
+        end
+
+        it "has CreatedAt" do
+          expect(data).to serialized_as(serializer_class,
+            "CreatedAt" => created_at)
+        end
+      end
+
+      context "with key_type + method_fields" do
+        let(:serializer_class) do
+          Class.new(Panko::Serializer) do
+            attributes :created_at
+
+            def created_at
+              "2023-04-18T09:24:41+00:00"
+            end
+          end
+        end
+
+        it "has CreatedAt" do
+          expect(data).to serialized_as(serializer_class,
+            "CreatedAt" => created_at)
+        end
+      end
+    end
+  end
 end